MEXICO CITY (Reuters) -Mexico's president on Tuesday picked veteran U.N. diplomat Alicia Barcena to be the country's new foreign minister after Marcelo Ebrard resigned to focus on his campaign to become the ruling party's candidate in next year's presidential election.

A trained biologist, Barcena served for nearly 14 years as executive secretary of the United Nations' Economic Commission for Latin America and the Caribbean (ECLAC), and has been Mexico's ambassador to Chile since last September.

"She's a professional, a diplomat, a woman with convictions, with principles," President Andres Manuel Lopez Obrador told a press conference as he announced her nomination. "And she's going to help us in this last stretch of the government."

Lopez Obrador, whose term in office will conclude on Sept. 30, 2024, said he expected the 71-year-old Barcena, whose qualifications include a master's degree from Harvard's Kennedy School of Government, to begin her new role in 10 days.

Barcena was the longest-serving head of ECLAC, according to the commission's website. Prior to that job she served in a range of U.N. roles.

The new foreign minister's appointment must be ratified by the Mexican Senate, which should be a formality. In the interim, Deputy Foreign Minister Carmen Moreno will take charge of the ministry, Lopez Obrador said.

Ebrard last week announced his plan to step down as foreign minister in order to seek the presidential nomination for the leftist National Regeneration Movement (MORENA), which is heavily favored to win the June 2024 elections.

Barcena had long been tipped as a potential successor to Ebrard if he left the post to campaign. Late last year she withdrew from the race to be president of the Inter-American Development Bank, citing personal reasons.

(Reporting by Dave Graham and Stefanie Eschenbacher; Writing by Sarah Morland; Editing by Paul Simao)